Conventional peanut and other nut butters typically consist of a mixture of solid nut particles, liquid oil, and other optional ingredients including flavorants, an emulsifier and a stabilizer. The primary component of peanut butter, peanut paste, is generally prepared by roasting, blanching, then grinding shelled peanuts. The grinding operation breaks the cellular structure of the peanut kernels, liberating oil in which the comminuted nut particles are suspended to form a peanut paste having a pasty and spreadable consistency. The flavorants, emulsifier, stabilizer and other optional ingredients are then added to the peanut paste to provide a peanut butter having a desirable taste and consistency.
Consumers consider a number of factors when evaluating the desirability of peanut butter. One very important factor is "peanut flavor" perception. Although the flavor of the nut paste can be that of the natural (raw) nut, the desired flavor is more typically developed by subjecting the nuts to a thermal operation such as roasting. For example, peanuts can be roasted in a hot air convection roaster (e.g., a Jet Zone.TM. roaster manufactured by Wolverine). The roast temperature and the roast time control the nut flavor character and intensity.
Generally, roasting peanuts at a higher roast temperature and shorter time results in the most desirable peanut flavor. Roasting peanuts at higher temperatures creates a non-uniform temperature profile and, in turn, a non-uniform flavor profile within the peanut (darker roast outside and lighter roast inside). This non-uniformity produces a peanut flavor more desirable than that of peanuts roasted to the same color but at a lower roast temperature. However, there is a limit to the amount of peanut flavor that can be developed by this approach.
Because of the non-uniform roast profile within the peanut, roasting to a darker roast color to further intensify peanut flavor can cause over-roasting of the outer peanut, leading to undesirable burnt and bitter flavors. Past efforts to intensify peanut flavor by over-roasting required the use of high levels of sweeteners such as sucrose to diminish the negative over-roasted flavors. However, the level of sweetener required to mask the over-roasted flavors was so great that excessive sweetness resulted and/or the product fell outside the peanut butter standard of identity.
Another factor important to consumers is "stickiness" perception. The consumer perceives "stickiness" as the peanut butter's adhesion to the roof of the mouth, as well as the effort required for the tongue to remove it therefrom. Stickiness perception is related to the viscosity of the nut butter. U.S. Pat. No. 5,714,193, issued Feb. 3, 1998 to Fix et al. (Adding Oil To Nut Paste Prior to Homogenization To Reduce Viscosity and Stickiness Without Loss of Nut Flavor), herein incorporated by reference, teaches that stickiness perception can be reduced by decreasing the viscosity of the peanut butter.
The particle size distribution (PSD) of the nut solids affects the resulting peanut butter viscosity. Peanut butters made by finely milling the nut solids to a mono-modal particle size distribution have relatively low viscosities. See U.S. Pat. No. 5,079,027, issued Jan. 7, 1992 to Wong et al. (Roll-milling Nut Solids To A Mono-modal Particle Size Distribution), and U.S. Pat. No. 5,508,057, issued Apr. 16, 1996 to Wong et al. (Process Of Making Monomodal Nut Butters And Spreads), both herein incorporated by reference. Conversely, coarser grinding to a poly-modal (or multi-modal) particle size distribution produces a more viscous peanut butter. A poly-modal particle size distribution results in increased particle packing behavior and a greater tendency of the nut particles to collide with each other under stress. In addition, coarser grinding of the nuts ruptures fewer oil cells, resulting in less free oil in the nut solid suspension. These factors cause the resulting poly-modal peanut butters to be more viscous than, and therefore stickier than, mono-modal peanut butters.
Unfortunately, prior efforts to reduce peanut butter viscosity have also led to a significant reduction in peanut flavor intensity, creating an undesired trade-off between stickiness reduction and peanut flavor. For example, chunky type peanut butters made with larger, coarsely-ground peanut granules have more peanut flavor than creamy style peanut butters, but the processing conditions creating these larger particle size peanut solids generally lead to stickier peanut butters. Conversely, finely grinding the nut solids to reduce viscosity, and in turn reduce stickiness, decreases peanut flavor. It is believed that peanut flavor release is a function of the extent that the nut solids are hydrated. During the mastication process, a less sticky peanut butter product is in the mouth for a shorter period of time, thus reducing the degree of hydration of the nut solids and, in turn, leading to a decrease in peanut flavor.
Accordingly, consumers have experienced a long-felt need for a product providing more peanut flavor with a reduced stickiness impression.